Using Powder Cores to Increase the Power Density of Flyback Storage Transformers

Abstract:
Flyback converters are widely used in low to medium power converters. The flyback-storage-transformers – the heart of the converters - are traditionally based on gapped ferrite cores. In this paper we present powder cores as an alternative, which can be used to increase the power transferred through a flyback storage transformer of the same size, using their higher usable flux density. It is mentioned, how the soft saturation behaviour and core losses have to be respected during the design. On a 100kHz flyback we demonstrate a concrete example which underlines the theoretical findings.